顱內動脈瘤 (Intracranial aneurysm) 是一種腦血管疾病。在美國約有萬分之一的人因顱內動脈瘤破裂而產生蜘蛛網膜下腔出血 (subarachnoid hemorrhage, SAH)，使病患產生噁心、嘔吐與視覺異常等症狀，較嚴重者還可能導致中風。血管栓塞手術為現今治療顱內動脈瘤的主流方式，在手術過程中，導線 (guidewire) 必須在有限的時間內藉由x光導引至顱內動脈瘤之病理位置，然而，在導線行徑過程中需要通過彎曲複雜的血管，因而經常會與血管壁接觸與摩擦，導致感染及併發症的發生。本研究對顱內動脈瘤治療提出改良方法，為了完整瞭解顱內動脈瘤內之流場情況與探討新型的治療方式，本研究除了利用數值模擬方式進行血液動力學 (hemodynamic) 分析，探討顱內動脈瘤之流場分布與應力分布以提供血管栓塞手術之參考依據，同時，為了改善在血管栓塞手術中導線遠端自由度不足而對血管壁造成的損傷，本研究設計出一種易於製造的形狀記憶合金微型致動器，利用形狀記憶合金遇熱形變之原理，有效的控制導線遠端彎曲，降低導管介入性治療所造成之血管損傷以及感染與併發症發生的機率。結果顯示本研究之微致動器之最大彎曲角度可達到23.3°、最大橫向彎曲位移量可達到908 µm，並藉由血管模型之實驗，說明了本實驗之微型致動器具有微型化的尺寸、較佳的彎曲角度與可信賴的量化數據以應用於導管介入性治療。

Endovascular coiling has been expletively used for the treatment of an intracranial aneurysm. In the aforementioned treatment, under the guidance of x-ray, a specifically trained neurosurgeon manually navigates the guidewire through patient's vascular network to place the coiling in the desired position. However, blood vessels of the brain are highly complicated networks, making it difficult for the surgeons to manually navigate the guidewire, which upsurges the possibilities of vessel damage and infection. In this aspect, numerical simulation was conducted to elucidate the hemodynamics of a patient-specific intracranial aneurysm model to delineate the possible location of vessel damage. Subsequently, a shape memory alloy (SMA) based actuator was designed and embedded with the commercially available guidewire to navigate it through the complicated vasculature network. The efficacy of the SMA actuator embedded guidewire was tested, and experimental results illustrate that the miniaturized actuator gives an optimal bending angle of 23.3° and a lateral displacement of 908 µm, a reasonable maneuverable ability towards computer guided control. In addition, the miniaturized actuator was tested in a patient-specific vascular network model to provide its efficacy as well as to demonstrate its appraised feasibility during catheter interventions.

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